Stacking consecutive similar neuroendovascular cases is associated with reduced turnover time and procedure time

Across a wide range of tasks it has been shown that workers switching between different activities have 'switching costs' due to slower performance and increased errors. Scheduling similar cases consecutively, or 'stacking cases', allows an operating room (OR) team to avoid switching costs and might therefore result in increased efficiency.

To investigate whether stacking neuroendovascular cases decreases turnover and procedure time.

A retrospective case series was identified of 4386 endovascular cases performed by vascular neurosurgeons between 2015 and 2023 at an academic center. A 'stacked case' was defined as a binary variable, which counted as 'yes' when the preceding case was the same procedure. Primary outcomes were turnover time and procedure time.

Diagnostic angiograms (n=2575) and aneurysm embolizations (n=517) had a sufficient number of cases for statistical analysis.Stacked diagnostic angiograms were associated with significantly faster turnover time (7 min, P=1e-12) in a multivariate regression model. Turnover time decreased with additional stacked cases, with a 4 min reduction for a single stacked case, up to 11 min for a fifth stacked angiogram.For angiograms and aneurysm embolizations, stacked cases were associated with shorter procedure times: 4 min for angiograms (P<0.0001) and 20 min for aneurysm embolizations (P=0.0057).

This project demonstrates that stacking similar cases is associated with reduced turnover and procedure time, after controlling for other variables that affect the flow of an OR day. Stacking cases is a zero-cost intervention that offers significant efficiency gains in the OR schedule.